Recently, in the field of fitness and sport practice performed through gymnastic machines, the interest has been developed in providing gymnastic machines with respective video filming apparatuses, for visually and continuously monitoring a user during the execution of respective gymnastic exercises. These video filming apparatuses are usually constituted by an electro-optical filming device, for example a digital camera or an infrared sensor, and by a respective programmable control electronics allowing to set and adjust operating parameters of video filming and giving, typically in digital format and in real time, the flow of video data output from the filming device. The purpose of providing gymnastic machines with respective video filming apparatuses is that of visually and continuously monitoring at least one body portion, for example the face, of the user during the execution of gymnastic exercises. More in particular, the use of a digital camera or a webcam to frame the face of a user of gymnastic machine can allow him/her to perform live video-calls or videoconferences/video-chats during training. This opportunity is particularly desirable during prolonged cardiovascular training sessions, during which a user, in addition to reading or listening to music, could be interested to communicate with other people.
Alternatively, the opportunity of monitoring, during training, the face or another body portion of a user of a gymnastic machine through specific cameras or opto-electronic sensors, for example infrared sensors, allows to acquire in real time biometric information about the user, for example his/her heart rate.
However, it should be noted that, independently of the purpose of the visually and continuously monitoring of a given body portion of a user during training, the video monitoring apparatuses currently available on the market, and their respective algorithms for tracking a moving object, present limits that do not allow a satisfactory use thereof in the sector of gymnastic machines. In fact, during a training session with a gymnastic machine the face and the other body portions of a user continuously move, and are therefore movable also inside the visual field of the filming device or they can also exit it, thus making literally impossible a continuous monitoring of the body portion. In this regard, with reference to the common digital cameras available on the market, it should be noted that algorithms are known for digital analysis of the images, that allow to detect, and also to emphasise, the face of the filmed subject; however these algorithms usually require at least some tenths of a second to analyse a single image, and they cannot therefore be used to analyse a film, i.e. a series of frames in rapid succession, with a speed sufficient to track a face moving inside the visual field of the films.
Consequently, by providing a gymnastic machine with a video monitoring apparatus among those currently available on the market, it is not possible to monitor continuously and in real time a face or another body portion of a user, as the generally available control electronics of the video filming device and the algorithms for analysing the images are not suitable to track stably and in real time this body portion during the execution of the training session. As a result, this instability in tracking the body portion does not allow the body portion to be displayed correctly in real time, and does not allow a correct evaluation of the biometric parameters of the user during training.
In view of the situation described above, the problem of performing, continuously and substantially in real time, a video monitoring of a moving body portion of a user of a gymnastic machine during a respective training session, is therefore currently unsolved. In this regard, it would be desirable to have available a video monitoring method that can be implemented through any video monitoring apparatus associated with a gymnastic machine for visually and continuously monitoring a body portion of a user of the gymnastic machine during the execution of physical exercises. More in particular, it would be desirable to have available a video monitoring method that allows tracking, effectively and stably over time, a moving body portion so that this latter is constantly framed substantially in the centre of the visual field of the used monitoring apparatus.